He-111H-11

Medium Bomber

Heinkel

The He 111H-11 from a structure 6./JG53, taking part in supply of the surrounded grouping of Germans in area of Hill mountain, February, 1942.

It could be encountered in the East as often as the more modern and faster Ju 88. Several times damaged machines landed in territory Soviet troop units controlled, and were carefully examined. But, as a rule, the situation would not allow aircraft to be evacuated deep into the rear area.

Two Heinkels that Red Army soldiers captured on an airfield west of Stalingrad were selected for this testing program. After reconditioning, an He 111H-6 bomber was turned over to Chkalovskaya for testing on 24 February 1943, but, after the third flight, an engine malfunctioned. Institute engineers then began working with the second aircraft—an He 111H-11, which had its worn-out engines replaced by those from another Heinkel. In May 1943, this airplane safely completed the program (lead engineer Major G. V. Gribakin, lead pilot Lieutenant Colonel G. A. Ashitkov).

Testing showed that, despite its reheated Jumo 211-F-1 engines with a takeoff power of 1350 hp, the He 111H-11 had maximum level speed, rate of climb, and ceiling which were rather low for the year 1942. The German bomber lagged behind the domestic series-produced 11-4 by 11-19 km/h in speed (depending on altitude) and by 3.9 minutes in climbing to 5000 meters (given a normal flight weight for both planes). It also compared unfavorably with the Soviet bomber in cruising range with a 1000-kilogram bomb load.

But, in some respects, the Heinkel had definite advantages. It had improved defensive armament with an increased number of guns, including the MG 131 machine gun and MG-FF cannon in a semi-fixed mount. Collimating sights replaced the simple ring and bead gun sights. The ammunition supply for the semi-fixed machine gun mount on Soviet bombers permitted 15 seconds of uninterrupted fire, whereas a German gunner could fire for 75 seconds before running out of ammunition.

Engineer-Major Gribakin did not think that the German airplane was sufficiently armored in area and in thickness for protection against large-caliber rounds and projectiles (the weight of armor varied from 270 to 315 kilograms, depending on bomber modification). Nevertheless, armor plates protected the crew, the most important and vulnerable units of the power plant, and the crew working area, thus enhancing the bomber's viability. Striving to increase the bomb load and size, German designers decided not to make complicated modifications to the He 111H-11 fuselage and switched to external bomb racks at the expense of aerodynamic qualities. An additional fuel tank took the place of bomb bay in the fuselage.

The Il'yushin Experimental Design Bureau installed VISH-61IF-1 feathering propellers (instead of the standard VTSH-2 3) on an 11-4 bomber being tested at the
Air Forces Scientific Research Institute almost simultaneously with the Heinkel. These propellers began to be used after examining German know-how when a disabled engine propeller was feathered to facilitate flight on one working engine. The testing team thought that the main 11-4 defects were insufficient longitudinal stability, ducking down when the split landing flaps were extended, inconvenient radiator gill control, and weak undercarriage wheels. All this made the 11-4 more difficult than the He 111 to handle.

References

"The German Imprint on the History of Russian Aviation " /D.A. Sobolev, D.B. Khazanov/